Maggie had reflux as a baby and one of the best things for her was to wear her in sling. It calmed her down, kept her upright so she was not in so much pain and the movement helped lull her to sleep. It also allowed me to get a few things done.

Also, as already suggested, try music. You may have to try a few type to find out what your DS likes. Maggie likes UB40, Robert Miles and Moby. In the early days she would really settle with a massage to Medieval meditative music. If you can't get to a baby massage class see if your local MCHN has a video on it you can borrow or if your local library has one.